Condylar Growth Research Articles

The PI3K/Akt signalling pathway may play an internal role related to abnormal condylar growth: a preliminary study

Developmental deformity of the mandible is one of the most common craniofacial malformations and is closely related to abnormal condylar growth. In this study, the role of PI3K/Akt signalling in the regulation of chondrocyte proliferation and hypertrophic differentiation in the condylar cartilage was studied. Immunohistochemical staining was used to investigate the expression of PI3K and p-Akt in the rat condyle cartilage. Rat condylar chondrocytes were cultured for the investigation of chondrocyte proliferation and hypertrophic differentiation when PI3K/Akt was inhibited. In addition, organ culture of the rat mandibular condyle was performed to evaluate the condyle cartilage growth while PI3K/Akt was inhibited. PI3K-positive cells and p-Akt-positive cells showing cytoplasmic staining were found to be present in the condylar cartilage. Reduced cell proliferation was observed in the culture of rat condylar chondrocytes when PI3K/Akt was inhibited; however, the hypertrophic differentiation level was increased. The proliferative zone thickness of condylar cartilage in the experimental group was less than that in the control group (P=0.00185), but the hypertrophic zone was greater than that in the control group (P=0.01048). PI3K/Akt signalling exerts opposite influences on chondrocyte proliferation and hypertrophic differentiation of the condylar cartilage, and these data suggest that PI3K/Akt is a potential intracellular regulation signal pathway in condylar cartilage development.

A cohort study of patients with juvenile idiopathic arthritis and arthritis of the temporomandibular joint: outcome of arthrocentesis with and without the use of steroids

The purpose of this study was to evaluate the effects of intra-articular temporomandibular joint (TMJ) treatment in patients with juvenile idiopathic arthritis (JIA). The inclusion criteria were met by 21 patients (38 joints). Joints were randomly selected for either arthrocentesis alone (n=17) or arthrocentesis with the additional use of triamcinolone hexacetonide (n=21) using a closed single-needle system. Measurements of pain and function were performed at baseline and at follow-up after 3 and 8 months. Pain on opening and lateral excursion improved significantly after injections. Pain decreased significantly from baseline to first and second control on a visual analogue scale (VAS) for overall pain (49–18–8) and overall function (41–19–4). Significant improvement was recorded for pain on palpation of muscles and joints. There was no statistically significant difference between the treatment modalities, with or without glucocorticoid injection. Arthrocentesis in the TMJ treatment of patients with JIA may be beneficial and steroids had no additional effect. Further studies are needed to evaluate the long-term effects on the TMJ structures and on condylar growth from arthrocentesis and intra-articular steroid injections.

Surgical Treatment of Hemimandibular Hyperplasia Leading to Unilateral Overdevelopment of the Face

Introduction:: Hemimandibular hyperplasia is a facial deformity which may develop in any age and includes a unilateral enlarged mandibular condylar head, deviation of mandible and chins, elongated condylar neck or ramus, and an occlusal cant with open bite. Different surgical treatments are proposed in the literature from simple low or high condylectomy to more complex procedures combining osteotomies in different sites of the mandible. Surgical procedure is defined by the clinical evaluation and scintigraphic diagnosis of activity or inactivity in the center of condylar growth. Case Presentation:: This case report describes a 30-year-old female patient with left hemimandibular hyperplasia with activity of condylar growth, that was successfully treated with low condylectomy, asymmetric lefort I osteotomy and inferior border ostectomy on the affected side, and associated with a unilateral sagittal split ramus osteotomy on the contra-lateral side. Discussion:: The innovation on nerve dissection by removing the overlying buccal bone and performing inferior ostectomy under direct visualization of the nerve, proved to be a safe technique with a low risk of nerve damage.

Involvement of PI3K/Akt pathway in rat condylar chondrocytes regulated by PTHrP treatment

ObjectiveThe aim of this study was to explore the mutual communication of the parathyroid hormone-related peptide (PTHrP) and phosphatidylinositol 3-kinase/threonine protein kinase (PI3K/Akt) pathway on the proliferation and differentiation of condylar chondrocytes from Sprague-Dawley (SD) rats. MethodsCondylar chondrocytes from the condylar cartilage were cultured and an organ culture system of mandibular condyles was employed. The distribution of PI3K, phospho-Akt (p-Akt), and PTHrP in condylar cartilage was detected by either immunohistochemistry or immunofluorescence. The second passage chondrocytes and condyle specimens in the organ culture system were treated with PTHrP, LY294002, PTHrP and LY294002 in combination, or dimethyl sulfoxide (DMSO), separately. The mRNA and protein levels of type II (Col II) and type X collagen (Col X) were investigated by real-time polymerase chain reaction (PCR) and Western blot analysis. The condyle growth in organ culture system was analysed by haematoxylin–eosin staining. ResultsPTHrP, PI3K, and p-Akt were mainly located in the proliferative and hypertrophic zones. PTHrP promoted the proliferation of condylar chondrocytes, while LY294002 limited this effect. The mRNA and protein levels of Col II and Col X in these cells were reduced by PTHrP and enhanced by LY294002. Organ culture showed a significant enhancement of condyle elongation with PTHrP treatment or a combination of PTHrP and LY294002 treatment. After treatment with LY294002, the length of condyles was reduced compared with the samples treated with DMSO. ConclusionsWe conclude that the PI3K/Akt pathway plays an essential role in the proliferation and differentiation of condylar chondrocytes and is a potential target for PTHrP in regulating chondrocyte differentiation at condylar cartilage.

Condylar response to functional therapy with Twin-Block as shown by cone-beam computed tomography

To evaluate the condylar changes through cone-beam computed tomography (CBCT) images in patients treated with Twin-Block functional appliance. In this retrospective study, CBCT images of 30 patients who were treated with the Twin-Block appliance were used. Mandible was segmented and pretreatment and posttreatment (T0 and T1) condylar volume was compared. The angle between sella-nasion-Point A (SNA), angle between sella-nasion-Point B (SNB), angle between Point A-nasion-Point B (ANB), midfacial length (Co-A), mandibular length (Co-Gn), and the distances from right condylion to left condylion (CoR-CoL) were also measured on three-dimensional images. Differences were analyzed with Wilcoxon signed rank tests, and Mann-Whitney U-tests were used to compare the scores of male and female participants. Significance was set at P < .05. In this study, a decrease in SNA and ANB (P < .05 and P < .01, respectively) and an increase in SNB (P < .01) were found. Additionally, CoR-CoL, Co-Gn, and condylar volume increased at both the left and right sides (P < .01). However, increase at Co-A was not statistically significant (P > .05). Comparison of differences by sex was not statistically significant for all measurements (P > .05). Twin-Block appliance increases condylar volume, mandibular length, and intercondylar distance by stimulating growth of condyle in an upward and backward direction.

Evaluation of effects of activator treatment on mandibular growth by analyzing components of condylar growth and mandibular rotation

PurposeThe objective of this study is to clarify the effects of activator treatment on mandibular growth in relation to condylar growth and total rotation of the mandible, and to investigate the relationships between the treatment responses and pretreatment facial morphology. Materials and methodsThirty Japanese girls with Class II division 1 malocclusion treated with activator were examined. Mean age at the start of treatment was 9.6±1.6 years. Mean treatment duration was 19±4 months. Lateral cephalograms obtained before and after treatment were used to analyze skeletal changes during treatment. Regional superimposition analysis was performed to evaluate activator effects by decomposing the mandibular growth into condylar growth and mandibular total rotation. ResultsThe changes in intermaxillary relationships were significantly correlated with vertical condylar growth and mandibular total rotation (P<0.05 and P<0.01). The changes in the forward displacement of the mandible were significantly correlated with sagittal condylar growth and mandibular total rotation (P<0.05 and P<0.01). Vertical condylar growth and mandibular total rotation were significantly correlated with pretreatment mandibular morphology (P<0.05 and P<0.01). ConclusionBoth the sagittal condylar growth and counterclockwise mandibular total rotation attributed to activator treatment contribute to forward displacement of the mandible. The activator effects are expected greater in patients with flat mandibular plane, small gonial angle, backwardly inclined mandibular ramus and long posterior facial height.

Temporomandibular joint ankylosis: Case-series of two different surgical procedures

Introducation: The long-term outcome and clinical results of gaparthroplasty used for the treatment of condylar ankylosis of the mandible in children with application of postoperative activator appliances and costochondral rib graft are evaluated and compared. The purpose of this study was to compare the effect of gap arthroplasty and costochondral graft methods on reankylosis, a mount of mouth opening and growth. Materials and Methods: A non-randomized, retrospective clinical study of l0 cases (5-12 years old) of condylar ankylosis of the mandible, surgically treated during a 10 year period from 2002 to 2012 was performed. Four patients were treated by condylectomy and interpositional flap, whereas six were treated by condylectomy and immediate costachondral rib grafts. The first group underwent long-term postoperative therapy using removable activator appliances. Casts, radiographs, photographs, and computed tomography (CT) were used post surgically to evaluate rib graft, condylar growth and function, occlusion, facial, and condylar symmetry. Data were analyzed by SPSS 16 statistical software using Mann-Whitney, Paired T-test and Chi-square tests. Results: Children with long-standing condylar ankylosis of the mandible treated by condylectomy and interpositional flap showed more favorably when activators were used post-surgically. Conclusions: Gaparthroplasty with functional activator post-operatively can be considering for TMJ ankylosis.

Effect of nonviral plasmid delivered basic fibroblast growth factor and low intensity pulsed ultrasound on mandibular condylar growth: a preliminary study.

Objective. Basic fibroblast growth factor (bFGF) is an important regulator of tissue growth. Previous studies have shown that low intensity pulsed ultrasound (LIPUS) stimulates bone growth. The objective of this study was to evaluate the possible synergetic effect of LIPUS and local injection of nonviral bFGF plasmid DNA (pDNA) on mandibular growth in rats. Design. Groups were control, blank pDNA, bFGF pDNA, LIPUS, and bFGF pDNA + LIPUS. Treatments were performed for 28 days. Significant increase was observed in mandibular height and condylar length in LIPUS groups. MicroCT analysis showed significant increase in bone volume fraction in bFGF pDNA + LIPUS group. Histomorphometric analysis showed increased cell count and condylar proliferative and hypertrophic layers widths in bFGF pDNA group. Results. Current study showed increased mandibular condylar growth in either bFGF pDNA or LIPUS groups compared to the combined group that showed only increased bone volume fraction. Conclusion. It appears that there is an additive effect of bFGF + LIPUS on the mandibular growth.

A Classification System for Conditions Causing Condylar Hyperplasia

A classification system was developed to place patients with condylar hyperplasia (CH) into categories based on histology, clinical and imaging characteristics, effects on the jaws and facial structures, and rate of occurrence. Four major categories were defined. CH type 1 is an accelerated and prolonged growth aberration of the "normal" mandibular condylar growth mechanism, causing a predominantly horizontal growth vector, resulting in prognathism that can occur bilaterally (CH type 1A) or unilaterally (CH type 1B). CH type 2 refers to enlargement of the mandibular condyle caused by an osteochondroma, resulting in predominantly unilateral vertical overgrowth and elongation of the mandible and face. One of the forms has predominantly a vertical growth vector and condylar enlargement, but without exophytic tumor extensions (type 2A), whereas the other primary form grows vertically but develops horizontal exophytic tumor growth off of the condyle (CH type 2B). CH type 3 includes other rare, benign tumors and CH type 4 includes malignant conditions that originate in the mandibular condyle causing enlargement. The order of classification is based on occurrence rates and type of pathology, where CH type 1A is the most commonly occurring form and CH type 4 is the rarest. This classification system for CH pathology should help the clinician understand the nature of the pathology, progression if untreated, recommended ages for surgical intervention to minimize adverse effects on subsequent facial growth and development in younger patients, and the surgical protocols to comprehensively and predictably treat these conditions.

Etiological factors in second mandibular molar impaction.

Objectives: The impaction of the second mandibular molar (MM2) has recently become more prevalent. Several etiological hypothesis have been proposed to investigate the association between skeletal features and impaction of MM2. The aims of this study were to analyze the skeletal features in patients with MM2 impaction and the association between arrested eruption of MM2 and the presence of the third mandibular molar (MM3). Study Design: In this retrospective study 48 subjects from 3,530 Caucasian orthodontic patients with MM2 impaction were included in a study group (SG) and compared to a control group (CG) of 200 subjects without MM2 impaction. Panoramic radiographs evaluated the presence or absence of the MM3 germ. Cephalometric analysis was performed to evaluate linear and angular skeletal values. For the statistical analysis, descriptive statistics, Student’s t-test, χ2 test and odds ratio (OR) were used. Results: The paired comparisons between SG and CG showed in cephalometric analysis both a reduced mandibular gonial angle (ArGoMe) and lowered Jarabak’s polygon value with a statistically significant difference (P≤ 0.05). MM3 was statistically significant associated (P≤ 0.05) with MM2 impaction but it is not a risk factor (OR 0.817). Conclusions: Subjects with MM2 impaction show a vertical condylar growth direction. MM3 is not a risk factor for MM2 impaction. Key words:Impacted mandibular second molar, skeletal features, orthodontic.

The effect of local injection of the human growth hormone on the mandibular condyle growth in rabbit

The effect of local injection of the human growth hormone on the mandibular condyle growth in rabbit

The microstructural and biomechanical development of the condylar bone: a review

Bone constantly strives for optimal architecture. Mandibular condyle, which is subjected to various mechanical loads forcing it to be highly adaptive, has a unique structure and a relatively high remodelling rate. Despite the eminent clinical relevance of mandibular condyle, literature on its structural and biomechanical development and on the mechanical role of its mineralized and non-mineralized bone components is scarce. The aim of the present review is to provide a brief introduction to basic bone mechanics and a synopsis of the growth and development of human mandibular condyle. Subsequently, the current ideas on the relationship between the structural and biomechanical properties of bone in general and of mandibular condyle in particular are reviewed. Finally, up-to-date knowledge from fundamental bone research will be blended with the current knowledge relevant to clinical dentistry, above all orthodontics. A comprehensive literature study was performed with an emphasis on recent and innovative work focusing on the interaction between microarchitectural and micromechanical properties of bone. Mandibular condyle is a bone structure with a high bone turnover rate. Mechanical properties of mandibular condyle improve during adolescence and are optimal during adulthood. Local mineralization degree might not be a decisive determinant of the local bone tissue stiffness as was believed hitherto. Bone collagen and its cross links play a role in toughness and tensile strength of bone but not in its compressive properties. Clinical procedures might affect mandibular condyle, which is highly reactive to changes in its mechanical environment.

Growth of the mandible and biological characteristics of the mandibular condylar cartilage

Mandibular condylar cartilage is the center of greatest growth in the craniofacial complex, and is associated with maxillofacial skeleton morphogenesis and temporomandibular joint function. The condylar process grows in a wide range of directions from anterosuperior to posterior, resulting in highly diverse mandibular growth and morphology. Condylar growth direction is closely related to mandibular displacement direction and vertical jaw deviations (i.e., high or low angle). Condylar cartilage, which is ontogenetically designated secondary cartilage, differs from other primary cartilage (e.g., articular cartilage and growth plate of a long bone cranial base cartilage, nasal septal cartilage) in the following ways. (1) Condylar cartilage is a heterogeneous tissue containing fibroblasts, osteochondral progenitor cells, and chondrocytes. (2) Type I collagen, which is derived from progenitor cells, and cartilage-characteristic type II collagen are colocalized in the cartilaginous cell layer. Colocalization of both collagen types may be an adaptation to the complex biomechanical environments of condylar cartilage. (3) Peripheral condylar cartilage contains chondroid bone, a specialized calcified tissue with morphological properties intermediate between those of bone and cartilage. This hybrid tissue may play an important role in regulating different rates of bone formation in intramembranous and endochondral ossification, allowing for highly diverse growth directions and condylar and maxillofacial morphology.

Condylar hyperplasia: our diverese experience

Condylar hyperplasia (CH) is a complex deformity affecting the condyle and the mandible. The resulting Facial asymmetry has a diverse presentation. We present patients with various degrees of asymmetry and malocclusion despite all being diagnosed with condylar hyperplasia. The treatment of this asymmetry is as variable as the the condition itself. However, the common ground is determining condylar growth activity first. We present our diagnostic methods using SPECT bone scan and the clinical methods.

Thin-plate spline analysis of mandibular morphological changes induced by early class III treatment: a long-term evaluation

To evaluate the long-term mandibular morphological changes induced by early treatment of class III malocclusion with rapid maxillary expansion (RME) and facial mask (FM). Twenty-five subjects [10 boys, 15 girls; mean age at T1 (start of treatment) 9.3±1.6 years] with class III disharmony were treated with RME and FM therapy followed by fixed appliances. The patients were re-evaluated at the end of growth (T2), about 8.5 years after the end of the treatment (mean age, 18.6±2.0 years). Sixteen subjects with untreated class III malocclusion comprised the control group. Mandibular shape changes were analysed on the lateral cephalograms of the subjects of both groups by means of thin-plate spline (TPS) analysis. Procrustes average mandibular configurations were subjected to TPS analysis by means of both cross-sectional between-group comparisons at T1 and at T2 and longitudinal within-group comparisons. Statistical analysis of shape differences was performed using a generalized Goodall F test. In the long term, the treated group exhibited a significant upward and forward direction of condylar growth. On the contrary, untreated class III subjects showed an upward and backward direction of condylar growth associated with a downward and forward deformation of the mandibular symphysis. Limitations are related to the small sample size of both treated and control groups and to the retrospective nature of the study. Early treatment of class III malocclusion with RME and FM is able to produce significant and favourable long-term mandibular shape changes characterized by an anterior morphogenetic rotation.

Morphological effects of mesenchymal stem cells and pulsed ultrasound on condylar growth in rats: a pilot study

Abstract Aim: The aim of this study was to assess and describe the morphological effects of an intra-articular injection of Mesenchymal Stem Cells (MSCs) and/or Low Intensity Pulsed Ultrasound (LIPUS) stimulation on the mandibular condyles of growing rats, using cone beam computed tomography (CBCT) and histology. Methods: Twenty-six young (23-day-old) rats were divided into 5 groups identified as LIPUS-stimulated (20 minutes daily using 50 mW/cm2, 1MHz, 0.2 millisecond pulses), MSCs injected (1 x 105 cells/kg), LIPUS + MSCs, medium injected, and untreated controls. All treatments were performed in the left temporomandibular joint of each rat (TMJs). At day 21, CBCTs were obtained for cephalometric analysis and 3D reconstructions. After animal sacrifice, left and right TMJ sections were histologically prepared and examined. The Wilcoxon sign rank test and the Kruskal-Wallis 2 test were applied for statistical comparison. Results: Imaging results showed that left condyles were wider in all LIPUS-treated groups (p &lt; 0.05), while the LIPUS-only group had a greater left sagittal condylar length. LIPUS-treated groups displayed a lower midline shift to the right (p &lt; 0.02). No significant differences were observed in the MSC group. Bone marrow morphology and vascularity differed between the groups as LIPUS-treated groups exhibited increased vascularity in the erosive cartilage zone. Conclusion: It was established that LIPUS and MSC application to the TMJ region of growing rats favoured transverse condylar growth, while LIPUS application alone may enhance sagittal condylar development. The MSC injection model had little effect on sagittal condylar growth.

Application of a Cephalometric Method to the Temporomandibular Joint in Patients With or Without Alteration in the Orientation of the Mandibular Condyle Axis

In a prior study,1 the spatial relationship of the mandibular condyle was studied through a cephalogram based on laminographies of the temporomandibular joint (TMJ). The present method was developed with the aim of analyzing TMJ morphology and the spatial relationship of the mandibular head within the mandibular fossa, considering references far from these structures, as they may suffer shape alterations. This study was conducted in view of the importance of the study of morphology and the hard structures relationship, which constitutes the temporomandibular joint. Its purpose is to validate a new TMJ cephalogram method by analyzing joints with and without alterations in the orientation of the condylar axis growth. Sixty joints were studied through laminographies in maximal occlusion, examining those joints with and without alterations in the orientation of the axis during condylar growth for subsequent analysis. Results showed that those joints were in a posterior position and rotation of the mandibular head, and that they presented a greater inclination in the articular eminence compared to joints without alterations in the axis orientation. Moreover, a new cephalometric method could be validated, demonstrating that changes in the condylar axis orientation imply pathology; they could also be correlated with changes in the condylar position and in the glenoid fossa morphology.

Early Intervention in Skeletal Class II and dental Class II division I malocclusion

A Class II malocclusion may occur as a result of mandibular deficiency, maxillary excess, or a combination of both. However, the most common finding is mandibular skeletal retrusion. The use of functional jaw orthopedics, at the right time during growth, can ultimately result in malocclusion patients achieving an excellent functional occlusion, a broad beautiful smile, a full face with a beautiful jaw line, and profile. Functional jaw orthopedic (FJO) appliances are designed to encourage adaptive skeletal growth by maintaining the mandible in a corrected forward position. The activator developed by Andresen is one of the most widely used for this purpose. A 12-year-old boy with skeletal Class II malocclusion and dental Class II div I malocclusion, a low mandibular plane angle was treated with growth modulation using an activator followed by molar distalization using fixed orthodontics for detailing of the occlusion. The major effects of the activator treatment in this case have been due to increase in condylar growth and also an increase in mandibular base length. Further, non-extraction fixed orthodontic treatment for proper interdigitation of the dentition also helped to maintain the stability of the satisfactory results achieved.

99mTc-MDP SPECT/CT for Assessment of Condylar Hyperplasia

We report a case of condylar hyperplasia diagnosed with 99mTc-MDP SPECT/CT. A 21-year-old woman with facial asymmetry was referred for assessment of condylar growth activity. SPECT/CT confirmed condylar hyperactivity, and simultaneous low-dose CT contributed to the diagnosis of hemimandibular hyperplasia. SPECT/CT may become a valuable tool for the diagnosis and comprehensive assessment of condylar hyperplasia, providing both functional and morphological information.

Increased mandibular condylar growth in mice with estrogen receptor beta deficiency

Temporomandibular joint (TMJ) disorders predominantly afflict women of childbearing age, suggesting a role for female hormones in the disease process. In long bones, estrogen acting via estrogen receptor beta (ERβ) inhibits axial skeletal growth in female mice. However, the role of ERβ in the mandibular condyle is largely unknown. We hypothesize that female ERβ-deficient mice will have increased mandibular condylar growth compared to wild-type (WT) female mice. This study examined female 7-day-old, 49-day-old, and 120-day-old WT and ERβ knockout (KO) mice. There was a significant increase in mandibular condylar cartilage thickness as a result of an increased number of cells, in the 49-day-old and 120-day-old female ERβ KO compared with WT controls. Analysis in 49-day-old female ERβ KO mice revealed a significant increase in collagen type X, parathyroid hormone-related protein (Pthrp), and osteoprotegerin gene expression and a significant decrease in receptor activator for nuclear factor κ B ligand (Rankl) and Indian hedgehog (Ihh) gene expression, compared with WT controls. Subchondral bone analysis revealed a significant increase in total condylar volume and a decrease in the number of osteoclasts in the 49-day-old ERβ KO compared with WT female mice. There was no difference in cell proliferation in condylar cartilage between the genotypes. However, there were differences in the expression of proteins that regulate the cell cycle; we found a decrease in the expression of Tieg1 and p57 in the mandibular condylar cartilage from ERβ KO mice compared with WT mice. Taken together, our results suggest that ERβ deficiency increases condylar growth in female mice by inhibiting the turnover of fibrocartilage.